ul,
li {
  list-style: none;
}

.nav_1st {
  width: 500px;
  height: 30px;
  line-height: 20px;
  padding: 5px 30px 5px 5px;
  border: 1px solid #000;
  background: url(./todown.png) no-repeat center right;
  background-size: 5%;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  margin: 0 auto;
}

.nav {
  width: 500px;
  line-height: 30px;
  border: 1px solid #000;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  position: absolute;
  top: 30px;
  right: 0;
  left: 0;
  margin: auto;
  z-index: 9999;
  display: none;
}

.nav_close {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 9990;
  display: none;
}

.nav li input {
  margin: 0 5px;
}

.nav li p:hover {
  background: #1e90ff;
  color: #fff;
}

.nav-2nd {
  padding-left: 37px;
}

#classification {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}